Keith Black KB258.030 80-Inch Evolution Flat Piston Kit .030

Keith Black flat top piston set is .030 oversize with an 8.6:1 compression ratio for 1984-up Big Twin Evolution models.

The Keith Black KB258.030 80-inch Evolution Flat Piston Kit .030 features a hypereutectic alloy piston cast in a permanent steel mold. This construction supports a lightweight piston design intended to help produce more power, improve fuel economy, and provide long service life.

The piston is .030 oversize for a 3.498-inch bore and has an 8.5:1 compression ratio. The alloy’s low heat transfer helps keep the skirts cooler and minimizes piston expansion. Combined with high compression ring placement, this design is intended to support power and economy while reducing detonation and increasing top-ring temperature.

For proper break-in, run the engine at moderate speeds for at least 500 miles and avoid excessive operation in lower gears. The Keith Black KB258.030 kit fits 1984–1993 Harley-Davidson FXR models as listed in the product data. Suggested item: 11-1366 80-inch Shovelhead Piston Ring Set .030.

Features:

• Brand: Keith Black
• Part Number: KB258.030
• Application: 80-inch Evolution engine
• Piston Type: Flat piston kit
• Oversize: .030 for a 3.498-inch bore
• Compression Ratio: 8.5:1
• Material: Hypereutectic alloy
• Construction: Cast in a permanent steel mold
• Design: Low heat transfer alloy with high compression ring placement
• Fitment: 1984–1993 Harley-Davidson FXR models
• Break-In Requirement: Run at moderate speeds for at least 500 miles and avoid excessive operation in lower gears

Fitment:
Harley Davidson FLST 1986
Harley Davidson FLST 1987
Harley Davidson FLST 1988
Harley Davidson FLST 1989
Harley Davidson FLST 1990
Harley Davidson FLST 1991
Harley Davidson FLST 1992
Harley Davidson FLST 1993
Harley Davidson FLST 1994
Harley Davidson FLST 1995
Harley Davidson FLST 1996
Harley Davidson FLST 1997
Harley Davidson FLST 1998
Harley Davidson FLT 1984
Harley Davidson FLT 1985
Harley Davidson FLT 1986
Harley Davidson FLT 1987
Harley Davidson FLT 1988
Harley Davidson FLT 1989
Harley Davidson FLT 1990
Harley Davidson FLT 1991
Harley Davidson FLT 1992
Harley Davidson FLT 1993
Harley Davidson FLT 1994
Harley Davidson FLT 1995
Harley Davidson FLT 1996
Harley Davidson FLT 1997
Harley Davidson FLT 1998
Harley Davidson FXD 1991
Harley Davidson FXD 1992
Harley Davidson FXD 1993
Harley Davidson FXD 1994
Harley Davidson FXD 1995
Harley Davidson FXD 1996
Harley Davidson FXD 1997
Harley Davidson FXD 1998
Harley Davidson FXR 1984
Harley Davidson FXR 1985
Harley Davidson FXR 1986
Harley Davidson FXR 1987
Harley Davidson FXR 1988
Harley Davidson FXR 1989
Harley Davidson FXR 1990
Harley Davidson FXR 1991
Harley Davidson FXR 1992
Harley Davidson FXR 1993
Harley Davidson FXR 1994
Harley Davidson FXST 1984
Harley Davidson FXST 1985
Harley Davidson FXST 1986
Harley Davidson FXST 1987
Harley Davidson FXST 1988
Harley Davidson FXST 1989
Harley Davidson FXST 1990
Harley Davidson FXST 1991
Harley Davidson FXST 1992
Harley Davidson FXST 1993
Harley Davidson FXST 1994
Harley Davidson FXST 1995
Harley Davidson FXST 1996
Harley Davidson FXST 1997
Harley Davidson FXST 1998